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Coefficient of relatedness (r)

Definition
AI-generated

Probability an allele chosen at random in one individual is identical by descent (IBD) to an allele drawn at the same locus from another individual; under standard diploid pedigree conventions it equals twice the [Kinship Coefficient](../k/kinship.md).

Topics
Population genetics
Synonyms
Coefficient of relationship (same symbol *r* in much of the pedigree literature) Relatedness coefficient
Related
Coefficient of Relationship Identity by Descent (IBD) Kinship Coefficient

Why it matters in GWAS

Expected r from pedigrees and empirically estimated r or kinship from genotypes drive relatedness QC, mixed models, and family-based association tests.

Example usage

"The pair’s coefficient of relatedness was consistent with first-degree relatives after excluding identity-by-state artefacts."

Coefficient of Relationship Identity by Descent (IBD) Kinship Coefficient Relatedness Coefficient
Related-term network

Click any node to open that term page.

Node order. The current term is first. Next come every page linked from Related terms, in the same top-to-bottom order as that list. Then new terms appear in two-hop layers: for each of those direct neighbors (in that same order), their related terms are appended if not already listed. A third pass does the same for two-hop nodes. The walk stops when a fixed maximum number of nodes is reached.

References

  • Hartl DL, Clark AG. (2007). Principles of Population Genetics. Sinauer Associates.
  • Jobling MA, Hurles ME, Tyler-Smith C. (2013). Human Evolutionary Genetics. Garland Science.
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